Routing of the exhaust begins where the DEI heat-wrapped headers end: with a ball-and-collar, gasketless connection. This short section of exhaust before the first weld utilize SpinTech's 2-1/2-inch oval tubing, which measures out at 1-3/4x3 inches.
The X-frame used by Chevrolet between 1958 and 1964 is especially hard to work around when designing and routing an exhaust system. Both sides of the exhaust are immediately run to the outside of the X-frame.
An advantage of the oval tubing is SpinTech was able to fit the exhaust above the low point of the frame by about a 1/4 inch. SpinTech also uses modern-style rubber hangers to suspend the tubing, allowing for metal expansion.
Looking inside a SpinTech muffler you’ll find SpinTraps, which provide the correct amount of backpressure as well as a pleasant exhaust note. After the two halves are welded together, the smaller six-trap unit on the right is what is typically used on Camaros and Mustangs, while you’ll find the larger eight-trap muffler on the left in larger vehicles, such as Impalas and trucks.
For this application (with the X-frame under a ’61 Impala), SpinTech miter cut a corner in their muffler to aid in routing and fitment.
With SpinTech exhaust systems, there is a male and female section to the tubing where the flanges meet up, making for a much better seal over other manufacturers who use only a gasket between the flanges.
As the exhaust nears completion, you can see how it follows the only open space in the Impala’s X-frame design.
SpinTech’s round-to-oval tubing allows them to convert a 2-1/2-inch exhaust into a 1-3/4x3-inch system with the added benefit of saving space.
Chris Anderson TIG-welds the over-axle part of the exhaust, where it twists from a horizontal plane to a vertical one and then back to horizontal.
In place, you can see what kind of clearance there is (not much!) between axle housing, coil spring, and frame, plus you have to consider the inside edge of the wheel, too.
Here’s the transition between the oval and back into a round piece for the tailpipe section.
For the tailpipe, SpinTech roughs out the routing by first tack-welding the sections together.
From there, measurements are made of each angle, and are transferred to a large machine (capable of bending 4-inch stainless!) that accurately bends a single piece of pipe into the desired shape.
The tailpipe now follows the shape of the roughed-in template part.
The single tailpipe section on the driver side looks factory in its presentation, and is finished with a down turn tip (used when you want the exhaust to disappear from view).
This photo shows both sides of the exhaust exiting on either side of the Impala’s gas tank.
The first step in wrapping an exhaust is to soak the wrap in a bucket of water. It makes it a bit more pliable, but it will also shrink a bit when it dries, thereby making a tight fit on the tubing.
At one end of the exhaust tubing, the wrap is folded under on itself for a clean start.
As you wrap the exhaust, you should be covering about half the width of what you just installed as you work your way down the pipe.
When you get to an end, fold the wrap under itself and secure it with a pair of DEI stainless steel locking ties.
Some folks like to secure their wrap with stainless steel safety wire, too. The installer used both methods on this exhaust.
The underside of the floorboards will be getting some of the heat shield material and, after making some paper templates, it gets trimmed and cut.
Here’s the area that was covered above each muffler. It goes on easily with its self-adhesive backing, but it’s wise to use a hard mini roller to tightly secure it to the floor.
Here’s the entire exhaust covered with heat wrap, and now the car is ready for the road.